We are currently testing DNA-based vaccines against falciparum malaria developed by Agracetus, Inc. These vaccines consist of a DNA sequences coding for the circumsporozoite protein of Plasmodium falciparum, a protein thought to be necessary for invasion of liver cells, and a hepatitis antigen known to be immunogenic. The DNA sequences are precipitated onto colloidal gold and shot through the skin of the monkey where the gold particles with the DNA expression vectors, lodge in the epidermis. This results in antigen production and the subsequent appearance of an antigen-specific immune response. Our preliminary findings indicate that two of the constructs are able to produce a reciprocal antibody titer of 12,800 after 1 booster vaccination at 14 weeks. Two other constructs yielded a titer of 3,200 and one yielded a titer of 6,400, all at 14 weeks after 1 booster injection. We have developed a lymphoproliferative assay to assess the cell-mediated response to these constructs, but have not seen a cellular immune response in the animals examined so far.